You need to know how old they are, the SDRAMS used for the parameter memories have a shelf life of about five to seven years. You can purchase replacements from Dallas Semiconductor but then you're left with the soldering, insulation and other technical challenges,...
Thermo Fisher (nee Eberline) has discontinued support of the E600 product line.
You will need an Eberline mini-pulser or compatible unit to calibrate an E600, there is a cutoff on the serial numbers which can support the E600, I would have to look that series number up. You would need all the RS232 and associated interface cables and the software programs are not compatible with MS products beyond XP.
What you have is a digital dinosaur. A nearly extinct digital dinosaur.
Too bad really, I made a good living off the E600 platform for the better part of a decade but, as with all things digital, obsolescence is only a few years away,...
Now, if you have the old Victoreen Civil Defence stuff you're golden, that stuff can readily be made serviceable just for fun,...
I have current contact numbers for folks at Thermo Fisher who are still knowledgable and may have some old stores available for E600 platform stuff, but it will not be cheap even if it is yesterday's news,...